(a) Field of the Invention
The present invention relates to an amphora-type particulate catalyst-support and to a method for the preparation of an amphora-type particulate catalyst-support.
More particularly the present invention relates to an amphora-type particulate catalyst-support which can be suitably used as a support for a variety of catalysts, including those to be used in the field of petroleum refining processes, especially in hydrotreatings, including hydrocracking, hydrogenolysis, hydrogenation, hydrofining, and the like of heavy oils such as atmospheric residuum, tar sands bitumens, shale oils, etc., and to a method for the preparation of the above-described amphora-type particulate catalyst-support.
(b) Related Art
Amphora-type particulate catalyst-support is a catalyst support comprising particles whose particle structure is characterized by near spherical or spheroidal form with a cavity (a space inside a particle) wherein the space inside the particle is opened to the space outside the particle through a single aperture (opening pore) at the outer surface of the particle. Because the structure of the particle resembles that of a roundish container having a cavity with a single opening such as an amphora, a bottle, an urceolate or the like, catalyst supports comprising particles of such a particular form have been represented by a term, "an amphora-type particulate catalyst-support".
Some known amphora-type particulate catalyst-supports have been preferably used as supports for certain catalysts because they are advantageous in respect of their large external surface area.
One of the known methods for preparing amphora-type particulate catalyst-supports have been disclosed in Japanese Patent Application Publication No. 58-10140. In this conventional method, amphora-type particles having an average particle size of 44 to 155 .mu.m are prepared by dropping small drops of a slurry comprising a component of a catalyst into a particle-bed.
Another known method for preparing an amphora-type particulate catalyst-support described in Japanese Patent Application Publication No. 58-31974 is a method which comprises the steps of (i) forming small drops of a slurry whose viscosity is in the range of about 400 to 8,000 centipoise, (ii) dropping the slurry drops to a stationary powder-bed under such conditions that a whole drop does not completely submerge in the powder, and (iii) drying the drops without stirring to obtain amphora-type particles having an average particle size of about 2 to 3 mm.
However, the amphora-type particles prepared by the above-described methods have disadvantages or problems especially in the aspects that: their particle sizes are too large: the improvement in catalytic activity is not enough; and the mechanical strength of the particles is low in practical use.